Interventional drapes including surgical drapes serve to keep the area of the interventional procedure site as clean and sterile as possible. Most of the drapes feature, for that purpose, apertures formed according to the procedure site, the so-called fenestrations, or these can be correspondingly cut before the beginning of the procedure.
After the skin of the patient has been cleaned and disinfected, the drape is arranged with regard to the procedure site i.e. arranging the fenestration around the procedure site. The exact location of interventional procedure sites is visualised two- or three-dimensionally before the procedure takes place by MRI, MRT, X-ray or ultrasound in order to localize the target as precisely as possible and hereby, also to protect the surrounding tissue as much as possible.
This is illustrated for example by the statement of the National Institute for Clinical Excellence (NICE) on the use of ultrasound locating devices for placing central venous catheters (Technology Appraisal Guidance No. 49, September 2002) by stating that “Two-dimensional imaging ultrasound guidance is recommended as the preferred method for insertion of central venous catheters into the internal jugular vein in adults and children in elective situations.” A recently published study concludes that implementation of the NICE guidelines significantly reduces the number of complications observed during or after the insertion (Wigmore T J et al., Br J Anaesth. 2007 November; 99(5): 662-5).
The position of the exact procedure site can be marked and the device for visualisation removed before the procedure takes place. However, minor movements of the patient often change the location for the exact procedure site. Thus, in order not to loose the location of the procedure site before or during the procedure, real-time visualisation can be maintained during the entire procedure. Thus, the device for visualisation should be covered as sterile as possible in order to maintain a continuous visualisation of the target during the procedure.
In the field of ultrasonic guidance this has been solved by using a sterile cover for the ultrasonic transducer separate from the interventional drape as described in EP 1 104 618.
Additionally, US 2007/0267028 describes an interventional drape with a first fenestration and a fluid collection pouch where the interventional drape comprises at least one further fenestration for reception of a sterile cover for a means of reference e.g. infrared emitters and receivers protruding from the level of the surface of the drape whereby two- and three-dimensional visualisation systems can be used during the procedure. The means of reference are to be inserted from the side of the interventional drape facing the patient and are to be arranged before the procedure.
It is important due to the non-sterility of the device for visualisation that the cover is able to prevent any risk of contamination to the procedure site. Still, flexible movement is essential to obtain an exact visualisation of the anatomical target.